Veterinary hypodermic syringe



April 18, 1967 A. P. JOHNSON ETA.

VETERINARY HYFODERMC SYRNGE Filed DeC. 4 1965 his A110 ney INVENTORSALVIN P. JOHNSON JAMES W. KENNAN m .gm

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United States Patent O 3,314,428 VETERINARY HYPODERMIC SYRINGE Alvin P.Johnson, 11004 Mansel Ave., Inglewood, Calif. 90304, and James W.Kennan, Inglewood, Calif. (601 Paseo de los Reyes, Redondo Beach, Calif.90277) Filed Dec. 4, 1963, Ser. No. 328,002 7 Claims. (Cl. 12S-218) Thisinvention relates to hypodermic syringes and has for its principalobject the provision of a simple and eflicient electrically operatedsyringe, especially one intended for giving a plurality of successiveinjections, and providing forward thrust without -loss of medicationuntil the needle has reached its full penetration depth.

An object of the invention i-s to improve the veterinary 'hypodermi-csyringe illustrated in our Patent No. 3,051,- 173 dated Aug. 28, 1962,including replacing the iformer ball check valve in the piston by -arecess in the chamber section located so that the uid to ybe dischargedpasses Within the piston only after the piston has traveledsubstantially its full journey; standardizing the hub of the needleassembly while avoiding the usual taper t which unfortunately variesconsiderably in tolerance and therefore ability to seal; joining theneedle to the piston which moves with it as a unit in a manner tofacilitate separation of the needle and the pist-on without any toolsave a screw driver or a flat piece of metal.

Further objects of the invention include providing adequ-ate friction toprevent the needle `hub from dislodging under inertia and pressure, andmeans to discharge a few `drops of medication as the needle is withdrawnfrom the patient or other subject, this latter term lbeing broad enoughto include chickens, for example, as well as persons or veterinariananimals.

In the drawings:

FIGURE 1 is a central -section largely in side elevation;

FIGURE 2 is a view showing the piston-needle assembly in fully advancedposition.

FIGURE 3 is a side elevation of the piston-needle assembly on a largerscale and with the piston partly in section.

The syringe is of a type for -convenient handling much as in ourpreviously mentioned patent. The rear portion of the syringe consists ofa handle usually integral with the housing 11. The cylinder section issecured to the housing 11 by a tapered nut 12 threaded to a cylindricalextension 14 projecting forwardly from the solenoid case or housing. Thecylinder section 15 has in turn a threaded connection 16 with theforward or nose section of the syringe.

As in our Patent No. 3,051,173, the housing 11 contains a solenoid andits armature, the stem 18 of the latter, upon being energized as bypressing the trigger 19, advances plunger 21 putting pressure uponmedication chamber 22, the latter being located in the rear end ofcylinder section |15.

Needle-piston assembly includes a piston 26 havin-g a large forwardiiange 27 which limits both forward and Irearward movement of theassembly and at the rear a rubber quad ring 29 is provided located justbehind a plurality, preferably four, of slanting ports 30 whichcommunicate with the central passageway 32. The rear end of the pistonis .preferably domed or conical as at 33 for a purpose later to bedescribed. The piston in its ilanged front end has a groove 35 toreceive and hold an O-ring seal 36 which resiliently but firmly holdsthe needle head 38 to t-he piston So that these two always lmovetogether when the syringe is in use.

The needle proper 40 is of a standard size and is permanently joinedwith needle head 38, the -latter carrying a circular flange 39 justforward of circular portion 41 of 3,314,428 Patented Apr. 18, 1967 'icesmaller diameter spaced from piston flange 27 a sufficient distance toallow for reception of a piece of metal such as a can opener orpreferably a screw driver tip whereby the flanges 39 and 27 can byturning the screw `driver be separated -fby 1an amount such as to freethe needle portion from the piston portion, in other words to pry theneedle from the piston. The hub 42 oif the needle iits the central bore32 of the piston preferably quite snugly but in view of the O-ring seal36 appreciable tolerance may be al- -lowed if desired. The squeeze onthe O-ring sealing ring 36 is suicient to prevent displacement of thehypodermic needle yas the assembly is moved forward and the rear of the'hub or boss `42 is conical las at 43 in order to avoid a shoulder atthis point.

Chamber 22 is filled in 4desirable fashion as in our patent, hereindicated by the -ball check inlet nipple 46 which leads through passage47 to medication chamber 22 and is used only when the piston and theplunger are separated. The usual spring return (not shown) of thearmature and its plunger 21 has moved the latter t-o its rear positionat such time. An annular port groove 50 enlar-ges the bore 32 ofcylinder portion 15 near the forward end of the section and ispr-oximate a seal 51 halfway between the forward end of the rsection 15and the conical `beginning of port groove 50. The front face 54 ofcylinder section 15 forms a st-op against which the rear face of flange27 engages in normal position las the spring 55 urges the needle andpiston assembly toward its rear position as shown in FIG. 1. The `buffer5-6 resiliently forms a stop for limiting forward movement of theassembly as in FIG. 2.

In operation, current is admitted to the device through wires 57 whenthe trigger 19 is pressed. This causes the step 18 of the armature (thelatter not shown) to advance plunger 21 which has a channel shaped seal58 in radial section. Plunger 21 moving forwardly in chamber 22 pressesthe medication which in turn Aforces the needlepiston assembly to moveforwardly but does not allow any of the medication to pass into thecentral passageway 32 of the piston because of seal 29. Consequently,the needle-piston assembly moves forward against the fairly light spring55 in nose section 17 until flange 27 comes near to or against lbufferstop 56 at which time the four or -more slanting ports 30 and the se-al29 are within port -groove 50. Further movement of the plunger 21 nowforces the fluid into the central passage 32 of the piston through thebore of hulb 42 and into the relatively small canal of the needle andinto the subject.

As the uid pressure on the pist-on assembly is lowered the light spring55 returns the piston assembly a fraction of an inch so that seal 29 isseated within bore 32 in rear of ports 30 thus preventing air oranything else from entering the needle. This action is designed todischarge a few drops of medication as the ports 30 pass the port groove50 during the displacement time so as to insure that no transferral of-germs or other matter to the needle or to the medication chamber 22 ispermitted. The action requires but a minute portion of time and uponrelease of the trigger 19 the parts are almost instantaneously returnedto full rearward position by the spring (not shown) surrounding thearmature stem 18. At such time a fresh supply of medication is drawninto chamber 22 through nipple 46 as in our Patent 3,051,173.

What ywe claim is:

1. A hypodermic syringe 4comprising a medication chamber, a poweroperated plunger, one face of which forms the rear wall of the chamber,`a main bore cornmunicating with the chamber, and a needle-pistonassembly movable forwardly by fluid pressure as the plunger is moved,said piston having a `central bore through which medication passes tothe needle, said needle having a cylindrical hub fitting snugly in saidcentral bore and resilient coupling means rfor resisting separation ofthe hub and the piston, whereby the needle and the piston always move asa unit when the syringe is in use; said resilient coupling means beinglocated within the piston bore and engaging the `outer surface of theneedle hub.

2. The syringe of claim 2 in which the piston and the 11u-b havecooperating grooves and the resilient coupling means comprises an O-ringseated in both of said grooves.

3. A hypodermic syringe comprising :a discharge orilice, a medicationchamber, a power driven plunger forming the rear wall of the chamber,said syringe having a main bore discharging yfrom the Kmedicationchamber to the discharge orifice, a needle-piston assembly slidable insaid main bore and movable forwardly to project the needle into thedischarge orifice as the plunger is moved forward; said main borehavin-g an annular enlargement intermediate its ends forming a portgroove, said port groove having a trapezoidal radial section with thetwo shorter sides of the trapezoid converging outward, said pistonhaving an annular seal near its rear end and a plurality of slopingopenings :adjacent and spaced inwardly from said annular seal, proximateand alned with the forward sloping end of the port groove when theannular seal is centrally within said port groove, thus permitting fluidto pass through the forward portion of the needle-.piston assembly.

4. The syringe of claim 3 with light spring means within the syringe toreturn the piston assembly just suiTilciently to seat said annular sealin the Ibore, land thereby closing the medication chamber a-s the luidpressure on the piston assembly is lowered, whereby to discharge a fewdrops of medication as the openings pass the port -groove and thusinsuring .against transferral of. germs to the needle or to themedication chamber.

S. In combination, a piston having a flange at one end and a centralbore for receiving a fluid, with a hypodermic needle assembly having ahub slidable Within said bore, a seal resiliently holding the hu-'b inposition in the bore, said assembly including a holl-ow hypodermicneedle integral with the hub and having a flange spaced from the pistonflange to assist prying the assembly out of the :piston ybore by wedgingthe nan-ges apart' against the holding action of the seal.

6. The combination of claim 5 in which the piston has a domed end andhas a plurality of small passages equally Aspaced axially proximate thedomed end leading to the central bore.

7. The combination of Claim 6 in which the piston has a quad sealbetween the passages and the domed end.

References Cited by the Examiner v UNITED STATES PATENTS 2,399,1124/1946 Glover 239-205 2,591,046 4/1952 Brown 12S-218 2,704,073 3/ 1955Jensen 12S-218 2,752,918 7/1956 Uytenbogaart 12S-218.2 3,051,173 8/1962Johnson et al. 12S-218.2

ROBERT E. MORGAN, Acting Primary Examiner. DALTON L. TRULUCK, Examiner.

1. A HYPODERMIC SYRINGE COMPRISING A MEDICATION CHAMBER, A POWEROPERATED PLUNGER, ONE FACE OF WHICH FORMS THE REAR WALL OF THE CHAMBER,A MAIN BORE COMMUNICATING WITH THE CHAMBER, AND A NEEDLE-PISTON ASSEMBLYMOVABLE FORWARDLY BY FLUID PRESSURE AS THE PLUNGER IS MOVED, SAID PISTONHAVING A CENTRAL BORE THROUGH WHICH MEDICATION PASSES TO THE NEEDLE,SAID NEEDLE HAVING A CYLINDRICAL HUB FITTING SNUGLY IN SAID CENTRAL BOREAND RESILIENT COUPLING MEANS FOR RESISTING SEPARATION OF THE HUB AND THEPISTON, WHEREBY THE NEEDLE AND THE PISTON ALWAYS MOVE AS A UNIT WHEN THESYRINGE IS IN USE; SAID RESILIENT COUPLING MEANS BEING LOCATED WITHINTHE PISTON BORE AND ENGAGING THE OUTER SURFACE OF THE NEEDLE HUB.